1. Field of the Invention
The present invention relates to a cooling structure for an inverter device which may be mounted on, for example, an electrically powered automobile or the like.
2. Description of Related Art
In the standard automobile that is driven by an internal combustion engine, a radiator for cooling the internal combustion engine is generally provided within an engine compartment that is disposed in a front portion of the automobile body structure. In the case of the electrically powered automobile, no internal combustion engine is employed, but an inverter for a motor used to drive the automobile need be cooled since the inverter develops a heat during the use of such electrically powered automobile. Various techniques have hitherto been suggested such as, for example, a technique of liberating heats from the inverter by means of heat exchange with a supercharged air flowing through an intercooler (as disclosed in the patent document 1 listed below) and a technique of liberating heats from the inverter by means of the system in which, as shown in a conceptual diagram of FIG. 16, a medium heated by the inverter 70 is supplied to the radiator 72 through a piping path 71 so that the medium, cooled as a result of the heat exchange taking place in the radiator 72, may be supplied by the pump 73 to the inverter 70 to thereby cool.
[Patent Document 1] JP Laid-open Patent Publication No. 2010-184633
According to the conventional art, if the distance from the radiator 72 inside the bonnet to the inverter 70 on the automobile chassis is substantial, the piping path 71 becomes correspondingly substantial and, therefore, the flow resistance tends to increase to such an extent as to result in the increase of a load on a pump 73 for circulation. For this reason, it is difficult to downsize the pump 73. Also, since the inverter 70 is apt to emit heat less than that from the internal combustion engine, the capacity of the radiator 72 of a type that is mounted on the automobile of the same automobile classification tends to become large for the amount of heat generated by the inverter 70, resulting in over performance.